moving Google Drive folders

I need some advice on the best way to change Google Drive folder without re-syncing/downloading too much.

I have Syncdocs set up at my work (on c:) and home (on f: external hd). Now my f: drive is almost out of space so I am buying a new external hd. I want to move my Google Drive folder at home to the new hdd, and take the f: drive to work, and move my folders at work from c: drive to f: drive.
How can I set up both new drive and f: drive (already have all the files) without re-download the whole folders from Google Drive?